吲哚乙酸(indole-3-acetic acid,IAA)是色氨酸的代谢产物。为了探究IAA对神经炎症的调控作用,该研究建立了脂多糖(lipopolysaccharide,LPS)诱导的SH-SY5Y神经细胞炎症模型。首先通过细胞活性检测确定了LPS的诱导剂量,并检测了IAA对SH-SY5Y细胞活性的影响,然后利用蛋白免疫印迹测定了细胞中的炎症因子的表达情况,并对肿瘤坏死因子受体超家族成员25(tumor necrosis factor receptor superfamily 25,Tnfrsf25)/IκB激酶(inhibitor of kappa B kinase,IKK)/核因子κB(nuclear factor kappa-B,NF-κB)信号通路相关蛋白的表达水平进行检测。结果表明,低剂量的IAA不会影响SH-SY5Y细胞的存活率,超过200 μg/mL的IAA处理才会对细胞的存活率造成显著影响;IAA处理可显著抑制LPS引起的TNF-α和IL-1β的蛋白水平升高;此外,IAA可显著下调Tnfrsf25的蛋白水平,抑制IKK、IκB-α、NF-κB的磷酸化,表明IAA通过调控Tnfrsf25/IKK/NF-κB信号通路发挥抑制神经炎症的作用。该项目为阐明色氨酸代谢对脑部的保护作用提供了理论依据。
Indole-3-acetic acid (IAA) is a metabolite of tryptophan.To investigate the regulatory effect of IAA on neuroinflammation, this study established an SH-SY5Y neuroinflammation cell model induced by lipopolysaccharide (LPS).Firstly, the induction dosage of LPS was determined through cell viability assays, and the impact of IAA on the viability of SH-SY5Y cells was evaluated.Then, Western bolt was used to determine the expression of inflammatory factors and the expression levels of proteins related to the tumor necrosis factor receptor superfamily 25 (Tnfrsf25)/inhibitor of kappa B kinase (IKK)/nuclear factor kappa-B (NF-κB) signaling pathway in the cells.Results demonstrated that low dosages of IAA had no impact on the survival rate of SH-SY5Y cells;however, notable effects on cell viability were observed when the concentration of IAA exceeded 200 μg/mL.IAA treatment significantly inhibited the elevation of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) induced by LPS.Additionally, IAA markedly downregulated the protein levels of Tnfrsf25 and suppressed the phosphorylation of IKK, IκB-α, and NF-κB, indicating that IAA might exert inhibitory effect on neuroinflammation by modulating the Tnfrsf25/IKK/NF-κB signaling pathway.This study provides theoretical evidence for the neuroprotective role of tryptophan metabolism.
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